The changing incidence of cervical intra-epithelial neoplasia.

In order to determine whether the incidence of cervical intraepithelial neoplasia (CIN) was changing, statistics were obtained from the annual reports of the cytopathology laboratory at Groote Schuur Hospital, Cape Town, for the years 1979-1988 inclusive, and from the computerised records of the laboratory during 1987 and 1988. Analysis of 642,574 smears during the 10-year period showed an increase in incidence of human papillomavirus infection was noted. The follow-up of patients with CIN 3 was good. The peak incidence of CIN was in the 29-39 year age group. A high pick-up rate of CIN was noted in pregnant patients--10% had CIN 3. Smears from teenage patients, 78% of whom were pregnant, showed an alarmingly high incidence of atypical findings. The incidence of CIN is also high in the geriatric group of patients. These findings indicate that traditional teaching concerning cervical intra-epithelial neoplasia needs to be reviewed.